Spectroscopy and spectrometers may be used as various measurement and reference tools. They may use an array of measurement techniques on just about any form of matter. The measurement techniques may depend on the material of interest, which may dictate what frequency/wavelength may be best suited for the measurements. Spectrometers, for example, may be suited to measure emission or absorption spectrums. Further, absorption spectrometers may specifically look for characteristic absorption lines of the material. The absorption lines may be used to identify an unknown substance from a catalogue of known spectrums, or it may be used to detect the amount of that known substance in a sample. In general, spectroscopy principles may be used for various measurements or to define a reference based on frequency or wavelength.